New Times, Old Beliefs: Projecting the Future Size of Religions in Austria

Projecting the religious composition of the population is relevant for several reasons. It is akey characteristic influencing several aspects of individual behaviour, including marriageand childbearing patterns. The religious composition is also a driver of social cohesion andincreased religious diversity could imply a more fragmented society. In this context,Austria finds itself in a period of transition where the long-time dominant Roman-Catholicchurch faces a serious decline in membership, while other groups, particularly the secularsand the Muslims, increase their influence. We project religions in Austria until 2051 byconsidering relative fertility rates, religion-specific net migration, and the rate ofconversion between religions and transmission of religious beliefs from parents to children.We find that the proportion of Roman Catholics is likely to decrease from 75% in 2001 toless than 50% by the middle of the century, unless current trends in fertility, secularisationor immigration are to change. The share of Protestants is estimated to reach a levelbetween 3 and 5% in 2051. The most uncertain projections are for those without religiousaffiliation: they could number as little as 10% and as many as 33%. The Muslimpopulation—which grew from 1% in 1981 to 4% in 2001—will, according to ourestimates, represent 14 to 26% of the population by 2051. If current fertility trends remainconstant, Islam could represent the majority religion for those below 15 years of age in2051. Other religion categories are estimated to constitute 7-12% of the population by2051